Process for deoxidizing aluminum and its alloys



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ALBERT fiTRASSEB, OF ROESCHACH, SWITZERLAND.

PRQGESS FOR DEOXIDIZING ALUMINUM AND XTS ALLOYS.

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1 b all whom it may concern.

Be it known that l, Arena" Sruassnn, a citizen oi? Switzerland, residing at Rorschach, Canton of lot. Gall, Switzerland, have invented certain new and useful Improvem'ents in Processes for Ueoxidizing Aluminium and lts 11103 3, of which the following is a specification.

This invention has for its object to provide an improved process for deoxidizing aluminium and its alloys which consists in adding to the aluminium heated above its melting point, first an aluminium cartridge containing potassium phosphid (kalium phosphoricum) ion the purpose of con verting the in1pu.1.'itiiis,?j(consisting of Si, and Fe, and also 0) into phosphorus compounds; and then, i hen the aluminium has reached a still highertemperature, adding a second aluminium cartridge charged with one of the metals of the alkaline earths, for the purpose of oxidiz' g the phosphorus compounds. the rcsultin reaction being (T C3 such that the phosphorus compounds burn at the expense of the alkaline earth metal used, and the oxids form slag which floats on top of the aluminium, being insoluble in aluminium.

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The aluminium is heated to a temperature aoove its melting point, for instance to 800 degrees ccntigrade. Then an aluminium cartridge filled with potassium phosphid (helium phos *icum) is added to the bath of molten metal. Since the cartridge has a higher specific gravity than the liquid aluminium, the cartridge sinks to the bottom of the crucible and is melted there The potassium phosphid becoming thereby released, difi'uses throughout the bath of molten metal, and the impurities are converted by the phosphorus entering into reaction, into phosphor metals Without affecting the aluminium, because the afiinity of the phosphorus to aluminium is not so great as to the aforesaid metals Si and Fe.

The temperature of the aluminium is now raised to about 1100 degrees 0,, whereupon the second cartridge filled with one of the metals of the alkaline earths, such as for instance, calcium, barium, strontium, lithium, etc, is added to the bath of molten metal, (with generation of heat) with the oxygen resent as an im ourit in the aluminium specification of Letters Patent. l gmggntgfl A nt; 3,1929.

The alkaline earth metal combines a lication filed February 5, 1920. Serial No. 356,547.

and also with the phosphids ofSi and Fe, While the oxids of the metals Si and Fe, and the oxygen compounds of the aluminium rise, together with the respective metallic oxid, to the sur e of the metal bath and are no longer soluble in the latter.

This dcoxidation of aluminium produces a finer structure and a higher density of the metal.

As a consequence of mechanical. treatment of the deoxidized metal its tensile strength is thrice that of the metal before deoxidation.

Its electric resistivity is diminished, whereas its conductivity is increased, which is an important advantage especially in the case of electric line Wires.

The additions are used only in quantities up to 1.5 per cent, so that the Whole of the metal is consumed in the reaction, and none of the alkaline earth metal remains in solution in the a-luminium l i hat I claim is 1. A process for deosidizing aluminium and its alloys, which consists in first adding an aluminium cartridge containing, a phosphorus compound to the aluminium heated above its melting point, for the purpose of converting the impurities into phosphorus compounds, and then when the aluminium has reached a higher temperature, adding the purpose of oxidizing the phosphorus compounds, the reaction being such that the phosphorus compounds burn at the expense of the alkaline earth metal, and the oxids being insoluble in aluminium, float on the top of the latter.

2. A process for deoxidizing aluminium and its alloys, which consists in first adding an. aluminium cartridge containing potassium phosphid (kalium phosphoricum) to the aluminium heated above its melting point, for the purpose of converting the impurities (consisting of Si, Fe, and 0) into phosphorus compounds; and then when. the aluminium has reached a higher temperature, adding a second aluminium cartridge filled with one of the metals of the alkaline earths, for the purpose of oxidizing the phosphorus compounds, the reaction being such that the phosphorus compounds burn float on the top of the latter.

avsecond aluminium cartridge filled with 3. A process for deoxiilizing aluminium and its alloys, which consists in first adding an aluminium cartridge eontaining potassium. phosphid (liztllllhl phosphorieum) to the aluminium heated to NW) 'legie -s C. for the purpose of converting the impurities (consisting of Si. Fe, and 0) into phosphorus compounds, and then when the aluminium has reaeheil a higher temperature. adding a second aluminium Partridge filled with one of the metals of the alkaline earths. for the purpose ot oxidizing the phosphorus eonuioiuuls. the reaution being such that the phosphorus eonipoululs burn at. the expense oi the alkaline earth metal. and the oxirls being insoluble in aluminium, float on the top of the latter.

4:. A process for tleoxhlizing aliuniniuiu and its alloys, which consists in first adding an aluminium cartridge containing potassium plmsphiil (kaliuni phosphm'ieuin) to the aluminium heated aooxe its melting point, for the pin-pose of converting the impurities (consisting of Si, Fe. and 0) into phosphorus compounds, and then when the aluminium has reached a higher temperature, adding a seeoncl aluminium cartridge iillecl with calcium for the purpose of oxidizing the phosphorus compounds, the reaction being such that the phosphoruseonv pounds burn at the expense of the calcium, and the ()XillS being insoluble in aluminium, limit on the top of the latter.

In testimony whereof I have aflixeil my signature.

' ALBERT STRASQER. 

